Nickel(II) hydroxide: Difference between revisions

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 437323024

| Name = Nickel(II) hydroxide

| ImageFile1 = Hydroxid nikelnatý.PNG

| ImageName1 = Nickel(II) hydroxide

| ImageFile2 = Kristallstruktur Cadmiumiodid.png

| ImageName2 = Nickel(II) hydroxide

| IUPACName = Nickel(II) hydroxide

| OtherNames = Nickel hydroxide, Theophrastite

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo2_Ref = {{cascite|changed|??}}

| CASNo2 = 36897-37-7

| CASNo2_Comment = (monohydrate)

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = L8UW92NW6J

| EINECS = 235-008-5

| RTECS = QR648000

|Section2={{Chembox Properties

| Formula = Ni(OH)₂

| Appearance = green crystals

| Density = 4.10 g/cm³

| MolarMass = 92.724 g/mol (anhydrous) <br> 110.72 g/mol (monohydrate)

| Solubility = 0.0015 g/L<ref>{{cite book|isbn=0849304849|title=CRC Handbook of Chemistry and Physics|edition=84|pages=4–71|year=2003|publisher=CRC press}}</ref>

| SolubilityProduct = 5.48{{e|&minus;16}}<ref name="crc">{{cite book |author1=John Rumble |title=CRC Handbook of Chemistry and Physics |date=June 18, 2018 |publisher=CRC Press |isbn=978-1138561632 |pages=5–189|edition=99 |language=English}}</ref>

| MeltingPtC = 230

| MeltingPt_notes = (anhydrous, decomposes)

| MagSus = +4500.0·10⁻⁶ cm³/mol

|Section3={{Chembox Structure

| Structure_ref =<ref>{{cite journal|doi=10.1143/JPSJ.39.317|title=Magnetic Behaviours of a Random Magnet, Ni_pMg_(1-p)(OH₂)|journal=Journal of the Physical Society of Japan|volume=39|issue=2|pages=317|year=1975|last1=Enoki|first1=Toshiaki|last2=Tsujikawa|first2=Ikuji|bibcode=1975JPSJ...39..317E}}</ref>

| CrystalStruct = hexagonal, [[Pearson symbol|hP3]]

| SpaceGroup = P{{overline|3}}m1, No. 164

| LattConst_a = 0.3117 nm

| LattConst_b = 0.3117 nm

| LattConst_c = 0.4595 nm

| LattConst_alpha = 90

| LattConst_beta = 90

| LattConst_gamma = 120

| LattConst_ref =

| Coordination =

| Dipole =

|Section4={{Chembox Thermochemistry

| DeltaHf = −538&nbsp;kJ·mol⁻¹<ref name=b1>{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles |edition=6| publisher = Houghton Mifflin Company| year = 2009| isbn = 978-0-618-94690-7|page=A22}}</ref>

| Entropy = 79&nbsp;J·mol⁻¹·K⁻¹<ref name=b1/>

}}

|Section7={{Chembox Hazards

| ExternalSDS = [https://www.americanelements.com/printpdf/nickel-hydroxide-12054-48-7/sds External SDS]

| GHSPictograms = {{GHS07}}{{GHS08}}

| GHS_ref = <ref name="sds">{{cite web|title = Nickel Hydroxide|url = https://www.americanelements.com/nickel-hydroxide-12054-48-7|publisher = [[American Elements]]|access-date = 2018-08-30}}</ref>

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|302|332|315|334|317|341|350|360|372}}

| PPhrases = {{P-phrases|260|284|201|280|405|501}}

| NFPA-S =

| LD50 = 1515 mg/kg (oral, rat)

|Section8={{Chembox Related

| OtherAnions =

| OtherCations =

| OtherCompounds =

}}

'''Nickel(II) hydroxide''' is the [[inorganic compound]] with the formula Ni(OH)₂. It is a lime-green solid that dissolves with decomposition in [[Ammonia|ammonia]] and [[Amine|amines]] and is attacked by acids. It is electroactive, being converted to the [[Nickel oxide hydroxide|Ni(III) oxy-hydroxide]], leading to widespread applications in [[Rechargeable battery|rechargeable batteries]].<ref name="Chen">{{cite journal|author1=Chen, J. |author2=Bradhurst, D.H. |author3=Dou, S.X. |author4=Liu, H.K. |title= Nickel Hydroxide as an Active Material for the Positive Electrode in Rechargeable Alkaline Batteries |doi= 10.1149/1.1392522 |journal=Journal of the Electrochemical Society |year=1999|volume= 146|issue= 10 |pages=3606–3612|bibcode=1999JElS..146.3606C |s2cid=33058220 |url=https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1118&context=engpapers }}</ref>

==Properties==

Nickel(II) hydroxide has two well-characterized [[polymorph]]s, α and β. The α structure consists of Ni(OH)₂ layers with intercalated anions or water.<ref name=Oliva>{{cite journal|author1=Oliva, P. |author2=Leonardi, J. |author3=Laurent, J.F. |title=Review of the structure and the electrochemistry of nickel hydroxides and oxy-hydroxides|journal=Journal of Power Sources|year=1982|doi=10.1016/0378-7753(82)80057-8| volume =8|issue=2|pages= 229–255|bibcode=1982JPS.....8..229O }}</ref><ref name=Jeevandam>{{cite journal|author1=Jeevanandam, P. |author2=Koltypin, Y. |author3=Gedanken, A. |title= Synthesis of Nanosized α-Nickel Hydroxide by a Sonochemical Method|journal= Nano Letters|doi=10.1021/nl010003p|year= 2001|volume= 1|issue= 5|pages= 263–266|bibcode=2001NanoL...1..263J }}</ref> The β form adopts a [[hexagonal close-packed structure]] of Ni²⁺ and OH⁻ ions.<ref name=Oliva/><ref name=Jeevandam/> In the presence of water, the α polymorph typically recrystallizes to the β form.<ref name=Oliva/><ref name=Shukla>{{cite journal|author1=Shukla, A.K. |author2=Kumar, V.G. |author3=Munichandriah, N. |title= Stabilized α-Ni(OH)₂ as Electrode Material for Alkaline Secondary Cells |journal= Journal of the Electrochemical Society |year=1994|volume= 141|issue= 11 |pages= 2956–2959|doi= 10.1149/1.2059264 |bibcode=1994JElS..141.2956V }}</ref> In addition to the α and β polymorphs, several γ nickel hydroxides have been described, distinguished by crystal structures with much larger inter-sheet distances.<ref name=Oliva/>

The mineral form of Ni(OH)₂, [[theophrastite]], was first identified in the Vermion region of northern Greece, in 1980. It is found naturally as a translucent emerald-green crystal formed in thin sheets near the boundaries of idocrase or chlorite crystals.<ref name=Marcopoulos>{{cite journal|author1=Marcopoulos, T. |author2=Economou, M. |journal=American Mineralogist|year= 1980|volume= 66|pages= 1020–1021|url=http://www.minsocam.org/ammin/AM66/AM66_1020.pdf|title=Theophrastite, Ni(OH)₂, a new mineral from northern Greece }}</ref> A nickel-magnesium variant of the mineral, {{chem2|(Ni,Mg)(OH)2}} had been previously discovered at Hagdale on the island of [[Unst]] in Scotland.<ref>{{cite journal|author1=Livingston, A. |author2=Bish, D. L. |year=1982|title=On the new mineral theophrastite, a nickel hydroxide, from Unst, Shetland, Scotland|page=1|url=http://www.minersoc.org/pages/Archive-MM/Volume_46/46-338-1.pdf|journal=Mineralogical Magazine|volume=46|issue=338|doi=10.1180/minmag.1982.046.338.01|bibcode=1982MinM...46....1L |s2cid=8381523 }}</ref>

==Reactions==

Nickel(II) hydroxide is frequently used in electrical car batteries.<ref name=Jeevandam/> Specifically, Ni(OH)₂ readily oxidizes to nickel oxyhydroxide, NiOOH, in combination with a reduction reaction, often of a metal hydride (reaction 1 and 2).<ref name=Ovshinsky>{{cite journal|author1=Ovshinsky, S.R. |author2=Fetcenko, M.A. |author3=Ross, J. |title=A nickel metal hydride battery for electric vehicles|journal=Science|year= 1993|volume= 260|issue=5105|pages= 176–181|pmid=17807176|doi=10.1126/science.260.5105.176|bibcode=1993Sci...260..176O |s2cid=9523468 }}</ref><ref>{{Cite book|last=Young|first=Kwo|url=https://www.mdpi.com/books/pdfview/book/244|title=Nickel Metal Hydride Batteries|publisher=MDPI|year=2016|isbn=978-3-03842-303-4|language=en|doi=10.3390/books978-3-03842-303-4|doi-access=free}}</ref>

'''Reaction 1'''

{{chem2|Ni(OH)2 + OH(–) → NiO(OH) + H2O + e(−)}}

'''Reaction 2'''

{{chem2|M + H2O + e(−) → MH + OH(−)}}

'''Net Reaction''' (in H₂O)

{{chem2|Ni(OH)2 + M → NiOOH + MH}}

Of the two polymorphs, α-Ni(OH)₂ has a higher theoretical capacity and thus is generally considered to be preferable in electrochemical applications. However, it transforms to β-Ni(OH)₂ in alkaline solutions, leading to many investigations into the possibility of stabilized α-Ni(OH)₂ electrodes for industrial applications.<ref name=Shukla/>

==Synthesis==

The synthesis entails treating aqueous solutions of nickel(II) salts with potassium hydroxide. When the same reaction is conducted in the presence of bromine, the product is {{chem2|Ni3O2(OH)4}}.<ref>{{cite book|author1=O. Glemser|chapter=Nickel (II) Hydroxide and Nickel (II,III) Hydroxide|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=New York|volume=2|page=1549-1551}}</ref>

==Toxicity==

The Ni²⁺ ion is a carcinogen when inhaled.

* [[List of minerals named after people]]

* [[Nickel–cadmium battery]]

* [[Nickel–hydrogen battery]]

* [[Nickel–metal hydride battery]]

* [[Nickel–iron battery]]

==References==

{{reflist}}

{{Hydroxides}}